The advent of fiber optics has provided an opportunity for miniaturization and refinement of medical endoscopic tools for cardiopulmonary, orthopedic, gastroenterologic, gynecologic, urologic, and general surgical applications. The evolution of design continues to aid in the diagnosis and treatment of a variety of disorders.
An endoscope by Masaaki Terada as described in U.S. Pat. No. 3,960,143 discloses an endoscope that permits the passage of medical instruments for a surgical operation. The multilayered tubes have low frictional coefficient materials for transmission of instruments within an outer flexible tube. The overall diameter of the endoscope appears to be in the neighborhood of 20 millimeters.
A later design by Michael Bass et al in U.S. Pat. No. 4,146,019 provides for the removal of blood clots and the like while observing an operation. Their endoscope has a number of internal channels for illuminating, viewing, flushing, evacuating and operating. The many features of the Bass et al endoscope make the diameter dimension in the neighborhood of one-half inch.
A still later design by Termanini in U.S. Pat. No. 4,204,528 permits the illumination or selected portions of the cardiovascular system and the injecting of a clear fluid for observation purposes. An extendable and retractable irrigation head passes a clear solution to reduce the opacity of the blood and thereby increases the diagnostic capabilities of physicians. The outside diameter of the catheter is approximately eight millimeters.
Thus, there is an unmet need in the state-of-the-art for an endoscope having a reduced diameter and flexibility in the neighborhood of two millimeters to allow the diagnosis and treatment of ureteral and renal disorders.